A being as inert as MotherBrain isn't an obvious choice for an end boss, particularly in a series that has become renowned for such all-time great monstrosities as Ridley and Kraid. And despite her triumphant appearances in the original Metroid and in the classic cartoon show Captain N: The Game Master, MotherBrain didn't come into her own until the release of Super Metroid in 1994. A spiky brain in a jar: good. A spiky brain atop a biomechanical T-rex skeleton shooting lasers and spewing bombs: fantastic.

It helps that the climax of Super Metroid still stands as one of the best examples of in-game storytelling ever. MotherBrain has Samus on the ropes, down to her last tank of health, when suddenly the giant Metroid swoops in and starts draining MotherBrain's energy. MotherBrain manages to destroy the Metroid, but not before it bestows upon Samus Aran one final thanks for saving its life: the Hyper Beam. And then, finally, Samus is finally able to give that bitch what for and live happily ever af–